Sunday, March 31, 2013

I have a bunch of carburetor parts to clean and recently read that Pine-Sol did a great job. So I tested it. Looking at the ingredients, I see this stuff is 1.75% glycolic acid. It did go right through my nitrile gloves and I had to switch to some heavy duty ones. And I did wear my safety glasses.
These parts have been soaked about 30 minutes, lightly scrubbed with a toothbrush and wiped off and then soaked for another 30 minutes. Then another light going over with a toothbrush and rinse with cold water. The part on the left is before cleaning, on the right is after.

Thursday, March 7, 2013

Somewhere on the web I bumped into a great idea to modify the Q4 spark arrestor to reduce the sound.
So I bought an extra spark arrestor for $35 and tried it out.
The idea is that you cut some slots in the end of the arrestor and bend the tabs over the block the pipe a bit. I used duct tape to mark where I was going to cut:

Here are a few shots of the modified spark arrestor next to an unmodified one:

Results:

FMF Q4 with Spark Arrestor

RPM Original Modified

2000 87 dB 87 dB

6000 102 dB 102 dB (whistle sound noticed on modified)

8000 106 dB 106 dB

No improvement! Wow, I really expected this to work. I guess I could bend the tabs down some more, but I don't want to crudely block the exhaust too much. I guess the lesson is that you need actual baffling, not just some blockage.

Another note is that these measurements with the original spark arrestor are different from the ones in my last post a couple days back. Just shows how variable this testing is.

Saturday, March 2, 2013

I decided to try a FMF Q3 Muffler (#045338) on my
2010 Husqvarna TE250. The FMF Q4 is an aluminum muffler for which they claim a maximum of 96 dB. This information probably applies to the other
4 stroke Huskys with an Arrow exhaust for 2011 and 2012 too, like the
TE310.

From the dealer, my Husky was pretty
quiet, but it had the catalytic converter and the throttle stop then.
If you follow the power up directions your remove both of those. And
then the bike is really loud, with just the stock spark arrestor. But
the power up directions also tell you to take the spark arrestor out
and to put the baffle that comes in the kit in the pipe. This does
make the bike a bit quieter.

So then you have a problem, if you like
a quiet bike. First, with the stock kit baffle the bike still is pretty loud.
Second, if you use the baffle, you don't have a spark arrestor.

“danbartol” on cafehusky did a
bunch of research and testing on this. His comments are here:

On the far right is the spark arrestor
that comes with the bike. The middle baffle comes in the power up
kit, and does quiet the bike down, but has no spark arrestor. (The
baffle on the far left is a part you can buy from husky. It does
quiet the bike down very nicely, but is very restrictive and still
has no spark arrestor.)

I ended up welding a mesh screen on the
end of the middle baffle (like Dan did), the one that came in the power up kit, and
I've been running that. Here is a shot with the screen:

But lately I've been going to some forests
and have been concerned that the cobby mesh wouldn't pass muster. And I
was hopeful that a Q4 from FMF might be quieter. And I also really
like reducing my bikes weight, and the Q4 was likely lighter than the
stock muffler.

Here was my setup. I roughly followed
the AMA standard, by attempting to put the meter 20 inches at a 45
degree angle from the pipe. But my meter is a cheapo and this is not
the right environment to test. All I was hoping to do was compare
the two pipes. Note these tests are very rough, with me just trying
to get the rpm right and then taking a quick look at the dB meter.

By ear, the FMF Q4 sounded deeper, with
the volume approximately the same as the stock exhaust.

So essentially, my results were very
similar to danbartol's. The benefit of the FMF Q4 is lighter weight
and a certified spark arrestor. The Q4 is no quieter and maybe louder than the stock exhaust
with the kit baffle. (Although by Dan's testing it's quieter
than the stock exhaust fully uncorked with no spark arrestor or baffle. That makes sense to me.)

Final shot of the installed FMF Q4 on
my TE250. The Pirie CF Pipe guard took some modification to get to
fit. I also removed the FMF stickers as they don't pay me to run their pipe ;-)